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= Learn GTK-rs

- The book:
  - https: #link("gtk-rs.org/gtk4-rs/git/book/introduction.html")

- Setup

  - Install gtk4
  - Find gtk version:
    - pkg-config –modversion gtk4

- Change feature of package "gtk4" to "v4_Y"

= Note

- Share state
  - Rc of Cell of state
  - Weak refernece
    - Pass something.downgrade to callback function
    - Upgrade weak reference before use it in callback
